Loose washers used with fasteners are misplaced within hardware assemblies in the aerospace industry. In some examples the hardware assemblies are subjected to extreme accelerations, changes in momentum and the like (e.g., in rocket propelled, satellite and other applications). Loose washers within these expensive assemblies become Foreign Object Debris (FOD). When accelerated and decelerated, especially in the case of rocket propelled electronics and other hardware, loose washers may cause extensive damage (e.g., through physical impact, as a fire or electrical hazard and the like) to hardware resulting in limited usability or outright failure of a device. Further, loose washers are hazards at times during assembly. Interaction between washers and assembly tools may create fire and electrical hazards with the risk of damaging or destroying sensitive hardware components. Even where washers are preassembled on fasteners (e.g., positioned along the fastener shaft or shank) there is a risk that delivery of the fastener to a location within the hardware will decouple the washer and create FOD. Disassembly of hardware to locate and retrieve washers is time consuming and expensive, and often results in uncertainty with regard to hardware quality and reliability.
Further, the assembly of washers with fasteners in the aerospace industry is often performed in a clean room with skilled and expensive manufacturing technicians. The assembly of washers and fasteners in such an environment is tedious and labor intensive, with technicians' level of difficulty increased by need to wear protective clothing such as rubber gloves or finger cots, surgical masks and the like. In some examples, using less expensive personnel and non-clean environments are not options as strict quality standards are required for assembly of the components used in the hardware.
In other industries, such as the automotive and electronics industries, preassembled washers and fasteners (SEMS) are used to facilitate efficiency in assembly. SEMS are preassembled by passing an unfinished fastener through a washer and thereafter deforming the fastener in another manufacturing step. For instance, as threading is formed on the fastener shaft (through dies, for example) the shaft is deformed and expands to engage with the washer. In some examples, the deformation of the fastener similarly deforms the washer and alters the physical properties of the fastener and washer including, but not limited to, the structural bearing of the washer, the torque needed to fastener the fastener and the like. Additionally, preassembled washer and fastener combinations in the aerospace industry require separate catalog entries and separate quality pedigrees for each of the permutations of the fastener, the washer and the fastener/washer combination. Stated another way, in the tightly controlled manufacturing and assembly processes of the aerospace industry the addition of preassembled fastener and washer combinations would require extensive rework or addition to product catalogs with corresponding development of quality pedigrees that would follow the preassembled combinations through manufacturing and assembly.